This relates generally to integrated circuits, and more particularly, to integrated circuits with decoupling capacitors.
Decoupling capacitors are often used to help provide more stable power supply voltages to circuitry on integrated circuits. Decoupling capacitors allow high frequency noise on direct current (DC) power supply lines to be shunted directly between the power supply lines, thereby preventing the noise from reaching powered circuit components. In a scenario in which a power supply is required to switch between various modes of operation, an adequate decoupling capacitance can act as an energy reserve that lessens the magnitude of undesired dips in power supply voltage during mode switching events.
Advances in integrated circuit design require power supplies to supply stable power for integrated circuits operating at high data rates and clock speeds. This requires increasing amounts of decoupling capacitance per integrated circuit area. A large decoupling capacitance could occupy a disproportionate amount of valuable surface area on an integrated circuit.
Conventional on-chip decoupling capacitors may be vulnerable to faults (defects). If a fault shorts a decoupling capacitor, an unacceptably large current could flow across the shorted capacitor rendering the integrated circuit unusable. Such a fault could arise during production or in the field as a result of a latent dielectric defect. As larger and larger decoupling capacitor arrays are implemented on integrated circuits, the chances that an integrated circuit will suffer from this type of defect will increase, resulting in an undesirable decrease in integrated circuit yield.
It would therefore be desirable to provide improved integrated circuit decoupling capacitor circuitry.